The present invention relates to apparatus capable of generating sensations as perceived by the brain during the performance of a movement affecting part or all of the body of a subject, while this same part of body is not actually being affected by any movement. The present invention concerns, inter alia, physical rehabilitation of persons, even certain animals, a damaged limb, or any other body part, part of which is immobilized by a corset. The present invention also relates to education and rehabilitation on functional movements that the brain no longer knows how to perform, or performs imperfectly, as a result of injury which is accidental or resulting from an illness, or due to a malformation.
The present invention also relates to the learning by an individual or an animal, of a body movement or gesture which has a specific purpose. It also relates to the addition to an individual's or an animal's received perception of a situation or a virtual event, of an additional type of sensory information. The term “virtual reality” is commonly used to describe such a confrontation of a subject with images, sounds and other types of sensory information, providing a descriptive representation of the situation or the virtual event. The invention is capable of causing a subject to perceive sensations corresponding to those of movement, whether or not the subject is performing these movements, which in effect constitutes additional sensory information for perception of virtual reality, and thus an enrichment of this perception.
A person with a broken upper or lower limb, or injured ligament, is usually fitted with a rigid corset that immobilizes the affected limb, such as a joint. When the corset is removed after a few weeks the relevant joint muscles are incapable of operating the movements they allowed prior to immobilization of the joint. This is due, firstly, to the fact that the muscles were injured or unused and, secondly, the fact that the brain has lost some of its ability to manage movements resulting from these muscles being brought into play. Indeed, many studies have shown that certain brain networks assigned to this task are progressively reassigned to other tasks if they fail to receive nerve messages sent by the skin and muscles when working. Physiological receptors located notably in the skin and muscles are responsible for issuing bioelectric messages to the brain. Specifically, some of these receptors are between muscle fibers and are located so as to be sensitive to the extension of the muscle. These messages are “reports” that describe the detailed movement of every muscle, so the brain can, in turn, have a representation of an action and control the muscles to eventually correct their movement and also to guide further movement in the desired direction.
Writing is a good example of such a feedback loop. The writer is simultaneously contracting or extending a number of muscles of the hand and wrist, all these elementary movements requiring, of course, to be perfectly coordinated. The brain senses, notably, messages issued by each muscle involved and the skin in case of extension, and it makes a synthesis of this information to determine what was, until then, the movement made, ie the path followed, in the case of writing.